Evaluation of BCG at birth in the United Arab Emirates

A total of 387 healthy full term infants who received BCG vaccination at birth were evaluated by the tuberculin PPD test at 6-8 weeks post vaccination. A total of 92% of these infants had visible BCG scars at that time. All infants were tested with PPD but only 264 returned for the test to be read. The tuberculin test was negative in 37 (14%) and of less than 5 mm induration in another 60 (23%) of the infants. The same pattern was observed in different nationalities. Of 11 infants with no BCG scar after vaccination, 3 had positive PPD reactions of more than 5 mm induration. There was a significant correlation between the size of the BCG scar and induration of tuberculin test P less than 0.001. The complications of the vaccination were minimal. We have observed 3 sterile abscesses at the site of BCG vaccination which resolved spontaneously. We think the available vaccine is safe and potent, and that the rate of BCG scar formation and of tuberculin conversion is higher than in most studies.     

Response to hepatitis B vaccine in preterm babies.

INTRODUCTION: A well-accepted vaccination schedule for preterm babies is not available. We therefore studied the response to hepatitis B vaccine in preterm babies. METHODS: 60 babies born to HBsAg-negative mothers were studied. Group I (n=20) consisted of term babies with birth weight >2.5 Kg, group II (n=20) included preterm babies with birth weight between 1.8 and 2.49 Kg, and group III (n=20) included preterm babies with birth weight between 1.2 and 1.79 Kg. Mean gestational age in the three groups was 38.5 (1.1), 33.5 (1.4) and 32.7 (2.1) weeks, respectively. All babies received 3 doses (10 microg/0.5 mL) of a recombinant HBV vaccine within 3 days of birth, and at 6 weeks and 6 months of life. Anti-HBs levels were measured one month after the 2nd and 3rd doses each; the immune response was categorized as good responders (anti-HBs >100 mIU/mL, low responders (anti-HBs 10-100 mIU/mL) and non-responders (anti-HBs <10 mIU/mL). RESULTS: Good antibody response after the second dose was seen in 95% of babies in group I, 60% of those in group II and 10% of those in group III. This increased to 100%, 90% and 45%, respectively after the third dose. The response was influenced by gestational age (r=0.73); 94% of babies with gestational age 34-36 weeks attained good antibody response compared to only 55% of babies with gestational age of 31-33 weeks. Birth weight had no independent influence on the antibody response. CONCLUSION: The response to hepatitis B vaccine is influenced by gestational age. Hence, in preterm babies, it is advisable to check antibody titers one month after the third dose to assess the need for a booster dose.     

BCG vaccination in low birth weight newborns: Analysis of lymphocyte proliferation,IL-2 generation and intradermal reaction to PPD

Objective: To study vaccinal scar formation and post-vaccinal immune response in newborns with birth weight ranging from 2000 to 2499 g vaccinated in the first week of life with intradermal bacille Calmette-Guérin (BCG) (Moreau-Rio de Janeiro strain).Method: Specific immune response to PPD was assessed in 30 low birth weight newborns (mean birth weight = 2311.7 ± 122.1 g; mean gestational age = 38.1 ± 1.8 weeks) in comparison to 56 control infants (mean birth weight = 3198.9 ± 267.2 g; mean gestational age = 38.5 ± 1.2 weeks).Results: Low birth weight infants have an efficient immune response to vaccinal stimulus when compared to control infants as judged by specific in vitro lymphocyte proliferation (mean SI = 9.7 ± 12.9 vs SI = 8.8 ± 10.0, P = 0.72) and IL-2 production (mean SI = 3.1 ± 3.4 vs SI = 2.6 ± 2.0, P = 0.38). Intradermal reaction to PPD was also comparable in both groups (mean induration diameter = 9.5 ± 5.1 mm vs 9.6 ± 5.0 mm, P = 0.94).Conclusion: These data suggest that low birth weight newborns show a good immune response to BCG, thus reinforcing the inclusion of such infants in regular vaccination programs with intradermal BCG.     

Tuberculin reactivity in a pediatric population with high BCG vaccination coverage.

SETTING: The tuberculin skin test (TST) is often included in diagnostic algorithms for tuberculosis (TB) in children. TST interpretation, however, may be complicated by prior Bacillus Calmette-Guerin (BCG) vaccination. We assessed the prevalence of and risk factors for positive TST reactions in children 3 to 60 months of age in Botswana, a country with high TB rates and BCG coverage of over 90%. METHODS: A multi-stage cluster survey was conducted in one rural and three urban districts. Data collected included demographic characteristics, nutritional indices, vaccination status, and prior TB exposure. Mantoux TSTs were administered and induration measured at 48-72 hours. RESULTS: Of 821 children identified, 783 had TSTs placed and read. Of the 759 children with vaccination cards, 755 (99.5%) had received BCG vaccine. Seventy-nine per cent of children had 0 mm induration, 7% had > or =10 mm induration ('positive' TST), and 2% had > or =15 mm. A positive TST was associated with reported contact with any person with active TB (odds ratio [OR] 1.9; 95% confidence interval [CI] 1.02-3.6), or a mother (OR 5.1; 95% CI 2.1-12.4) or aunt (OR 5.3; 95% CI 2.0-14.0) with active TB. TSTs > or =5 mm (but not > or =10 mm) were associated with presence of a BCG scar. Positive reactions were not associated with age, time since BCG vaccination, clinical signs or symptoms of TB, nutritional status, crowding, or recent measles or polio immunization. CONCLUSION: The TST remains useful in identifying children with tuberculous infection in this setting of high TB prevalence and extensive BCG coverage.     

Tuberculin skin testing of physicians at a midwestern teaching hospital: a 6-year prospective study.

The epidemiology of tuberculin reactivity among physicians practicing in regions of moderate tuberculosis prevalence is unknown. We prospectively assessed the epidemiology of tuberculin skin test (TST) reactivity among physicians in training in St. Louis between 1992 and 1998. Of 1574 physicians who were tested, 267 (17%) had positive TST results. Older age, birth outside of the United States, prior bacille Calmette-Guérin (BCG) vaccination, and practice in the fields of medicine, anesthesiology, or psychiatry were associated with a positive TST result. Among physicians born in the United States, 63 (5.7%) had positive TST results. Among physicians with > or = 2 documented TSTs, 12 had conversion to a positive TST (1.6%; 1.03 conversions per 100 person-years). Physicians in this study had a high rate of tuberculin reactivity, despite a low conversion rate. The relationship between TST conversion and birth outside of the United States and BCG vaccination suggests a booster phenomenon rather than true new TST conversions.     

The frequency profile of tuberculin skin testing among students in nursing school]

The frequency profile of tuberculin skin testing (TST) among students in nursing school was studied. Students received a TST upon matriculation. The TST was done by the method of Mantoux, in which 0.1 ml of PPDs was administered intradermally, and the diameters of skin rash and induration were read by the medical doctor at 48 hours. When TST results are negative--that is, the diameter of skin rash is below 10 mm (in Japan, the TST results are judged by skin rash diameter rather than that of induration)-BCG vaccination is given. Those receiving the BCG vaccination are retested with a TST one year later. When the second TST was also negative both the BCG vaccination and TST were followed for two more years. Those students testing TST-negative are not permitted to take clinical training in the tuberculosis ward. Student's mean age on entrance was 18.6 +/- 2.1 years old, and all but three were female. About 70% of students entering in 1996 to 1998 had a history of previous BCG vaccination. In 14% their positive TSTs could be attributed to probable infection with tuberculosis in childhood. In the remaining 16%, details as to TST and BCG vaccination status are unknown. The frequency distribution of TST results was bimodal, showing one peak at 6 mm and another at 12 mm (skin rash diameter). The percentage of negative and positive reactors are 47.1% and 52.9%, respectively. The TST-negative students entering in 1994 to 1996 were given the BCG vaccination. Twenty-four of 134 students (17.9%) remained negative at the second TST, and 6 students (4.5%) at the third year, even after two repeated BCG vaccinations. The TST results were chronologically observed in the above 6 students after BCG vaccination. The TST results of two students showed positive in September, 1996 and June, 1997. While four students showed positive in September, 1996, all ultimately reverted to negative when retested in June, 1997. Those students had negative results for TST at the initial test in 1998 had the two step-tuberculin skin testing. All eight students with negative TST had the history of BCG vaccination. The second TST showed positive except one student whose scar after BCG vaccination was not observed on the arm. The TST is currently recommended in hospital tuberculosis-control programs. If TST-negative, medical staff and students may not work in the tuberculosis ward. However, after BCG vaccinations is given, and subsequent TST conversion is confirmed, they are then able to work or to have training in the ward. From our results, there is 4.5% non-convertors even after 2 years of repeated BCG vaccinations. However, these non-converters turned positive four months after BCG vaccination, only to revert to negative nine months later. These students are considered to have delayed hypersensitivity to PPD after BCG vaccination. However, their reactivity waned in the short period of nine months after the conversion of their TST's. Therefore, it is concluded that non converters after repeated BCG vaccinations are able to have clinical training in the tuberculosis ward as long as their BCG vaccinations are correctly administered and any immunological deficiencies are ruled out.     

Avoiding the effect of BCG vaccination in detecting Mycobacterium tuberculosis infection with a blood test.

Bacille Calmette-Guérin (BCG) vaccination can confound tuberculin skin test (TST) reactions in the diagnosis of latent tuberculosis infection (LTBI). The TST was compared with a Mycobacterium tuberculosis (MTB)-specific enzyme-linked immunospot (ELISPOT) assay during an outbreak of MTB infection at a police academy in Germany. Participants were grouped according to their risk of LTBI in close (n = 36) or occasional (n = 333) contacts to the index case. For the TST, the positive response rate was 53% (19 out of 36) among close and 16% (52 out of 333) among occasional contacts. In total, 56 TST-positive contacts (56 out of 71 = 78.9%) and 27 TST-negative controls (27 out of 298 = 9.1%) underwent ELISPOT testing. The odds ratio (OR) of a positive test result across the two groups was 29.2 (95% confidence interval (CI) 3.5-245.0) for the ELISPOT and 19.7 (95% CI 2.0-190.2) for the TST with a 5 mm cut-off. Of 369 contacts, 158 (42.8%) had previously received BCG vaccination. The overall agreement between the TST and the ELISPOT was low, and positive TST reactions were confounded by BCG vaccination (OR 4.8 (95% CI 1.3-18.0)). In contrast, use of a 10-mm induration cut-off for the TST among occasional contacts showed strong agreement between TST and ELISPOT in nonvaccinated persons. In bacille Calmette-Guérin-vaccinated individuals, the Mycobacterium tuberculosis-specific enzyme-linked immunospot assay is a better indicator for the risk of latent tuberculosis infection than the tuberculin skin test.     

Management of patent ductus arteriosus in preterm infants.

OBJECTIVE: To evaluate the incidence of symptomatic patent ductus arteriosus (PDA) in preterm infants, and the results of the intravenous indomethacine treatment and surgery. METHODS: Among 394 preterm infants (<37 weeks), symptomatic PDA was diagnosed by echocardiography in 51 babies and they were examined retrospectively. All infants were managed conservatively and then IV indomethacine was given to non-responders (n=30). Surgical closure was performed in 12 babies. RESULTS: The incidence of symptomatic PDA in preterm infants was 12.9%: median age: 3 days, mean birth weight: 1434+/-540 g (540-2900g) and mean gestational age (GA) 30.9+/-3.3 weeks (23-37 weeks). With indomethacine, ductal closure was achieved in 70% infants. Early clinical improvement was observed in all cases that underwent surgery and most of them had a low birth weight (<1500 g) and an early gestational age (<32 weeks). None of them died due to operation. CONCLUSION: The incidence of symptomatic PDA is high in preterm infants. Treatment with indomethacine improves ductal closure and is associated with few reversible adverse effects. In the other hand, early clinical improvement and high success rate were achieved after surgery. If indomethacine fails to achieve ductal closure, decision of surgery must be made immediately.     

False-positive tuberculin skin tests: what is the absolute effect of BCG and non-tuberculous mycobacteria?

BACKGROUND: Despite certain drawbacks, the tuberculin skin test (TST) remains in widespread use. Important advantages of the TST are its low cost, simplicity and interpretation based on extensive published literature. However, TST specificity is reduced by bacille Calmette-Guérin (BCG) vaccination and exposure to non-tuberculous mycobacteria (NTM). METHODS: To estimate TST specificity, we reviewed the published literature since 1966 regarding the effect of BCG vaccination and NTM infection on TST. Studies selected included healthy subjects with documented BCG vaccination status, including age at vaccination. Studies of NTM effect had used standardised NTM antigens in healthy subjects. RESULTS: In 24 studies involving 240,203 subjects BCG-vaccinated as infants, 20,406 (8.5%) had a TST of 10+ mm attributable to BCG, but only 56/5639 (1%) were TST-positive if tested > or =10 years after BCG. In 12 studies of 12,728 subjects vaccinated after their first birthday, 5314 (41.8%) had a false-positive TST of 10+ mm, and 191/898 (21.2%) after 10 years. Type of tuberculin test did not modify these results. In 18 studies involving 1,169,105 subjects, the absolute prevalence of false-positive TST from NTM cross-reactivity ranged from 0.1% to 2.3% in different regions. CONCLUSIONS: The effect on TST of BCG received in infancy is minimal, especially > or =10 years after vaccination. BCG received after infancy produces more frequent, more persistent and larger TST reactions. NTM is not a clinically important cause of false-positive TST, except in populations with a high prevalence of NTM sensitisation and a very low prevalence of TB infection.     

Comparison of positive tuberculin skin test with an interferon-gamma-based assay in unexposed children

A false-positive tuberculin skin test (TST) may be a result of T-cell sensitivity due to Bacille Calmette-Guerin (BCG) vaccination or exposure to non-tuberculous mycobacteria, thus leading to unnecessary isoniazid preventive therapy, especially in low-risk populations. Unlike TST, T-SPOT.TB is not confounded by BCG vaccination or exposure to most of the other non-tuberculous mycobacteria, because this assay is based on enumeration of interferon-gamma-secreting T cells in response to Mycobacterium tuberculosis-specific antigens. We compared the TST with T-SPOT.TB with respect to different TST cut-off points in healthy unexposed BCG-vaccinated schoolchildren. A total of 209 children between 6 and 10 years of age with a TST induration of 0 (n = 50), 10 - 14 (n = 45), 15 - 19 (n = 95) and > or =20 mm (n = 19) were enrolled. Among TST-positive subjects, only 26 (23%) were positive with T-SPOT.TB, and T-SPOT.TB was positive in 4, 7, 20 and 42% of children with TST indurations of 0, 10 - 14, 15 - 19 and > or =20 mm, respectively. We suggest that confirmation of a positive TST by the interferon-gamma-based test would reduce unnecessary preventive therapy significantly in healthy unexposed BCG-vaccinated children.     

Poor correlation between tuberculin skin tests and interferon-γ assays in close contacts of patients with multidrug-resistant tuberculosis

Background and Objective: The results of tuberculin skin tests (TST) and QuantiFERON TB‐Gold In‐Tube (QFT‐GIT) assays were compared in close contacts of patients with multidrug‐resistant tuberculosis (MDR‐TB). Methods: Close contacts of patients with bacteriologically confirmed MDR‐TB (n = 101) were assessed. Most contacts were members of the households of patients, and 79 (78.2%) had received Bacille Calmette‐Guerin (BCG) vaccination. Samples from each contact were tested using the TST and the QFT‐GIT assay on the same day, and the concordance between these results was assessed using kappa (κ) coefficients. Results: Forty‐eight subjects (47.5%) showed positive responses on TST, using a 10‐mm induration cut‐off, and 54 (53.5%) were positive for the QFT‐GIT assay. Of the 48 individuals who were TST positive, 34 (70.8%) were positive for the QFT‐GIT assay. Of the 53 subjects who were TST negative, 33 (62.5%) were negative for the QFT‐GIT assay. The overall agreement between the two tests (κ coefficient) was 0.33. The κ coefficient was higher in the 22 subjects who had not received BCG vaccination (κ = 0.48) than in the 79 subjects who had received BCG vaccination (κ = 0.29). Conclusion: The TST and QFT‐GIT assays showed poor correlation in close contacts of patients with MDR‐TB, especially those contacts who had received BCG vaccination.     

QuantiFERON-TB Gold test for screening latent tuberculosis infection in hemodialysis patients

Hemodialysis patients are at increased risk of latent tuberculosis infection (LTBI) compared with the general population. QuantiFERON-TB Gold (QFT-G) for LTBI detection is more promising than tuberculin skin test (TST) in hemodialysis patients. The aim of this study is to determine whether the QFT-G is more sensitive than the TST in hemodialysis patients in LTBI. Eighty nine hemodialysis patients were evaluated for latent tuberculosis infection with the TST and QFT-G. Blood was obtained for QFT-G, and then TST was administered to all patients. Demographic information, laboratory tests, chest radiography results and BCG vaccination status were collected on standardized patient medical files. Forty patients had positive QFT-G results. 56 patients had TST induration above 5 mm, 28 patients above 10 mm. 61 patients had BCG vaccination scar. Statistically significant correlation was detected between TST and QFT-G (p< 0.05). In the BCG non-vaccinated subgroup, TST was positive in 8 (29%) patients and the QFT-G was positive in 11 (39%). Among the 21 non vaccinated patients with results for both tests, the concordance between the TST and QFT-G was 82%, k= 0.61, p= 0.001. We found good agreement between the TST and QFT-G test for LTBI in non vaccinated hemodialysis patients, whereas we found poor agreement in vaccinated patients. Because BCG vaccination is widely used in our country, the QFT-G test might be more useful for the diagnosis of LTBI than TST in hemodialysis patients who are suspected to have LTBI.     

Postnatal hemodynamic changes in low-birth-weight and very-low-birth-weight infants during the first 72 h of life

Background Despite increasing investigation in the area of cardiovascular instability in preterm infants,huge gaps in knowledge remain. Study of the hemodynamic characteristics in this population is inadequate. Methods A one-center, prospective, observational longitudinal cohort study at a third level Neonatal Intensive Care Unit enrolled 86 preterm infants. Of these, 46 were low-birth-weight(LBW) newborns of a mean(SD) gestational age of 32.3(1.1) weeks and a birth weight of 2,031(1,684-2,320) g. Forty were very-low-birth-weight(VLBW) newborns with a gestational age of 28.4(1.5) weeks and a birth weight of 1,255(884-1,580) g. All infants underwent Doppler ultrasound examinations at 24, 48, and 72 h after birth. Results SMII, DO_2, MBP, LVCO, CI, and SVI in the VLBW infants were all significantly lower than the LBW infants, but SVRI was not different. Postnatal increases in MBP, SVRI were observed in VLBW and LBW groups that were not associated with changes in LVCO and DO_2. The postnatal pattern of SMII differed between the two groups. SMII increased with postnatal age in the LBW group and did not change significantly in the VLBW group. Conclusions SMII and DO_2 were significantly lower in VLBW neonates during the first 72 h of life, and there was a direct relationship between inotropy, DO_2, and birth weight over a range of maturities at birth. VLBW infants may be at higher risk for cardiac dysfunction when an additional challenge is encountered.[S Chin J Cardiol 2019;20(4):245-251]     

Association of the growth hormone receptor d3-variant and catch-up growth of preterm infants with birth weight of less than 1500 grams

BACKGROUND: Preterm infants with very low birth weight frequently exhibit impaired longitudinal growth during the first years of life. Recently, the d3-isoform (genomic deletion of exon 3) of the GH receptor (GHR) has been linked to an increased responsiveness to GH. OBJECTIVE: Our objective was to test whether the GHRd3 isoform is associated with postnatal catch-up growth in very low birth weight preterm infants. DESIGN AND PATIENTS: We compared the postnatal growth pattern of 77 otherwise healthy preterm infants (mean gestational age, 28.5 wk; range, 23-35 wk) with a birth weight below 1500 g (mean birth weight, 941 g) to their GHR exon 3 genotype, which was analyzed by multiplex PCR. On examination, mean age of the children was 6.0 yr (range, 4.2-8.0 yr). RESULTS: Children homozygous or heterozygous for the GHRd3 allele showed a significantly higher rate of postnatal catch-up, compared with those homozygous for the full-length allele. CONCLUSIONS: Our results define the GHR exon 3 genotype as a predictor for the postnatal growth pattern of very low birth weight preterm infants. Those who carry at least one GHRd3 allele are more likely to catch-up.     

Tuberculosis infection in an Aboriginal (First Nations) population of Canada.

BACKGROUND: The incidence of active tuberculosis (TB) among the Cree, an Aboriginal population of Canada, is dropping, but it remains three times that of the general population. We analyzed data from tuberculin skin test (TST) surveys to determine estimates of prevalence of infection and annual risk of infection (ARI) in this population. METHODS: TST surveys targeting 12-year-old students were conducted annually from 1993 to 1998. Students with no record of previous positive TST (> or = 10 mm) were offered TST (5 TU PPD-T). Data collected included result of previous TST reading for all students, readings of TSTs performed (mm induration) and BCG (bacille Calmette-Guérin) vaccination status for those positive on TST. RESULTS: A total of 1274 children were screened (participation rate 94%). TST reaction size frequency distribution plots a bimodal curve. The prevalence of infection among 12 year olds was 15.3% over this period. ARI estimates range from 0.6 to 2.4% (average ARI 1.4%). A significant downward linear trend in ARI was observed over the period (P < 0.001). DISCUSSION: Calculated ARI may be over-estimated due to prior BCG vaccination; however, the trend in ARI confirms decreasing transmission of TB infection. Better knowledge of human immunodeficiency virus seroprevalence among pregnant women is needed to complete the evaluation of the BCG program.     

Tuberculin skin testing in BCG-vaccinated populations of adults and children at high risk for tuberculosis in Taiwan.

SETTING: Various populations at high risk for tuberculosis (TB) infection and with high bacille Calmette-Guérin (BCG) vaccination coverage in eastern Taiwan. OBJECTIVE: To investigate the usefulness of the tuberculin skin test (TST) to diagnose TB in BCG-vaccinated populations. DESIGN: Cross-sectional survey. RESULTS: TST reaction size was recorded for 444 individuals ranging in age from 8 months to 99 years, of whom 94.3% had scars to suggest previous BCG vaccination. The TST-positive (> or =10 mm) rate was increased in all comparisons of higher to lower TB risk, including household contacts (relative risk [RR] 3.52, P < 0.0001) and intermediate risk residents (RR 2.30, P = 0.030) compared to a lower risk control group. Advancing age was generally associated with increases in the TST-positive rate. Gender or the number of BCG vaccinations had no relation to the TST-positive rate. CONCLUSIONS: The results of this survey suggest that in eastern Taiwan a positive TST represents either active or latent TB infection rather than past BCG vaccination. Therefore, high BCG vaccination coverage in this region does not appear to limit the usefulness of the TST as a tool for diagnosing TB.     

Hepatitis B vaccination: long-term follow-up of the immune response of preterm infants and comparison of two vaccination protocols

Background: We conducted a 3-year follow-up study of long-term antibody persistence following vaccination of low-risk preterm infants with recombinant hepatitis B vaccine (HBV). Two three-dose protocols were compared: vaccination beginning within 24 h of birth to initial vaccination delayed until a weight of 2,000 g was reached. Patients and Methods: The study population included 136 children, divided into three groups: children born prematurely (≤ 35 weeks, n = 57), children born at term (≥ 37 weeks, n = 39), both groups receiving the first dose of HBV within 24 h of birth, and children born prematurely (≤ 35 weeks, n = 40), who received the first dose of HBV when a weight of 2,000 g was reached. All infants received the second hepatitis vaccination 1 month after the first, and the third dose 6 months after the first. Hepatitis B surface antibody (AntiHBs) was measured at an age of 3–3.5 years (at least 2.5 years after completion of the three-dose HBV series). An AntiHBs level of ≥ 10 IU/l was considered positive. Results: At 3–3.5 years of age, a higher percentage of the premature-delayed vaccination group had a positive AntiHBs level (92.5%) compared to both the premature (54.5%, p < 0.001) and full-term groups (71.8%, p < 0.05) vaccinated soon after birth. The premature-delayed vaccination group also had a significantly higher geometric mean concentration (GMC) (119 vs 14.2 IU/l, p < 0.001 and 119 vs 32.7 IU/l, p < 0.005, respectively). Conclusion: Delaying vaccination of premature infants against hepatitis B until a weight of 2,000 g was reached resulted in both a significantly higher percentage of children with positive antibody levels and a significantly higher GMC at 3–3.5 years of age as compared to early-vaccinated preterm and full-term infants. The known short-term advantage of delayed vaccination of preterm infants was shown to persist for at least the first 3 years of life. Received: July 12, 2001 · Revision accepted: January 8, 2002     

Prevalence and factors associated with tuberculosis infection among new school entrants, New York City, 1991-1993.

SETTING: New York City public (or state-run) and private schools-elementary and secondary. OBJECTIVE: To describe the prevalence and determine factors associated with positive tuberculin skin tests (TSTs) in school children. DESIGN: Mandatory TST surveys among cohorts of new school entrants for the 1991, 1992 and 1993 school years, of whom birthplace was known for 81%. A positive tuberculin skin test defined as > or =10 mm induration. RESULTS: Of the 298506 new school entrants, 2.1% (6326) were tuberculin test positive. The proportion that was tuberculin test positive was 0.5% (931/199 728) among US-born and 9.2% (3794/41 346) among foreign-born students. Foreign-born (FB) students with a history of BCG vaccination were much more likely to have a positive tuberculin test than US-born students (13.6% vs. 0.5%, odds ratio [OR] = 33.6, 95% confidence interval [CI] 31.7, 35.6), and were more likely to have a positive tuberculin test than FB students with no history of BCG (13.6% vs. 4.4%, OR = 3.4, 95% CI 2.5, 4.6). Older age was independently associated with tuberculin test positivity, except among foreign-born BCG-vaccinated children, in whom the youngest were more likely to have a positive tuberculin test. CONCLUSIONS: Even in the midst of a tuberculosis resurgence such as that experienced by New York City, where tuberculosis cases nearly tripled from 1978 to 1992, the risk of tuberculosis infection among school children remained quite low. Given the reduced predictive value of the tuberculin test among low risk children and the effects of BCG vaccination, many children (especially younger children) with positive tuberculin test results are probably not infected with Mycobacterium tuberculosis. To reduce unnecessary evaluation and treatment, routine tuberculin tests should be administered only to high risk groups such as older children from countries with high rates of tuberculosis.     

Positive tuberculin skin tests in nursing home residents in Southern Taiwan

In Taiwan, the tuberculin skin test (TST) is not recommended as a screening test for Mycobacterium tuberculosis (TB) infections. The aim of this study is to determine the prevalence and predictors of positive tuberculin reactivity and its association with TB infections among nursing home residents in Taiwan. A cross-sectional study and review of medical records were conducted at four nursing homes in Tainan City. A one-stage TST was performed by study nurses using two tuberculin units of purified protein derivative (PPD) of the RT23 strain. An induration ≥10 mm at 72 h was considered to be a positive reaction. Chest radiographs, acid-fast stains and mycobacterial cultures of three sputum samples were performed for those with a positive TST result. Of 115 residents (66.5% participation, mean age 73.1 years) who underwent a TST, 26 (22.6%) had a positive reaction. One woman was microbiologically diagnosed to have pulmonary TB. On multivariate analysis, a Bacille Calmette-Guérin (BCG) scar and a history of myocardial infarction were significantly associated with a positive TST. In conclusions, this study shows a considerable rate of positive TST among nursing home residents in southern Taiwan. A BCG scar and a history of myocardial infarction were associated with a positive TST.     

Clara-cell secretory protein in preterm infants' tracheal aspirates correlates with maturity and increases in infection

Clara-cell secretory protein (CCSP), produced primarily by Clara cells in the conducting airways, is the most abundant soluble protein in pulmonary lavage fluid. CCSP is thought to be an immunosuppressive or anti-inflammatory protein with protective functions in the respiratory tract against exaggerated inflammatory reactions. CCSP was measured in 98 tracheoalveolar fluid (TAF) samples from 24 preterm infants (gestational age, 27.9 +/- 2.3 weeks, birth weight 1,020 +/- 305 g) with respiratory distress syndrome during the first 2 postnatal weeks. The ratio of urea-N in serum and in TAF was used to correct for dilution of TAF samples. Concentration of CCSP in TAF when corrected for dilution increased from 3.6 +/- 11 microg/mL on day 1 to 29.6 +/- 6.9 microg/mL on day 14. CCSP correlated with gestational age. A negative correlation was found between CCSP and inspiratory oxygen concentration, and a positive correlation between CCSP and both arterial pH and base excess during the first 2 postnatal weeks. Infants with clinical and laboratory signs of infection had higher CCSP than noninfected infants, and a negative correlation was found between CCSP and leukocyte count during the first 2 postnatal weeks (all P < 0.05). We suggest that pulmonary CCSP correlates with both gestational and postnatal age, and increases in response to infection in infants with respiratory distress during the early postnatal period.